Double-loop four-pole directional element



July 10,1945. w. K. soNNEMANN ET AL 2,380,197

DOUBLELOOP FOUR-POLE DIRECTIONAL ELEMENT Filed Dec. 30,71943 ATTORN EY Patented July 10, 1945 DOUBLE-LOOP FOUR-POLE DIRECTIONAL ELEMENT William K. Sonnemann, Roselle Park, Arthur C. Mehring, East Orange, and Shirley L. Goldsborough, Basking Ridge, N. J., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 30, 1943, Serial No. 516,238

S Claims.

Our invention relates to single-phase loop-type directional elements in which two loops are uti-,- lized, developing torques out of phase with each other, so as to eliminate the double-frequency pulsating component of the torque, resulting in a smooth and reliable relay-operation. even at phase-angles which are close to the balance-point, or non-operating point, of the relay.

Heretofore, various multiple-loop relaymconu structions have been known, for eliminating tbe pulsating torque-component, as shown in Patent No. 2,300,886 of the applicant, Goldsborough, and Bert V. Hoard; in a pending application, ASerial No. 503,366, of the applicants, Goldsborough and Mehring, Iiled September 22, 1943; and in another pending application, Serial No. 504,696 of the aplicants, Mehring and Goldsborough, filed October 2, 1943. None of the previously known constructions, however, has utilized a single pair of fluxes, and two loops, in a perfectly symmetrical construction, with a single four-pole field-member, wherein it is possible to avoid all errors due to differences in the relative configurations and lengths and arrangements of the various magnetic circuits and poles and airgaps for the two fluxes and the two loops.

An object of our invention is to provide a symmetrical double-loop design which eliminates all possible errors in function and operation, whereby there may be produced two torques in which the double-frequency pulsations exactly neutralize each other, thus producing a non-pulsatory ren sultant-torque, regardless of the phase-angle between the current and the voltage applied to the relay-coils, or, more generally, regardless of the phase-angle between the two alternating-current exciting-currents which are supplies to the relay.

A further object of our invention is to provide a compact four-pole double-loop directional element which obtains the maximum possible torque lfrom both coil-sides of each loop, thus increasing the ratio between the torque and the inertia of the movable element, and thereby increasing the speed of operation of the relay, while at the same time totally eliminating the pulsatory double-frequency component of the torque.

With the foregoing and other objects in view,

our invention consists in the circuits, apparatus,

systems, parts, constructions and methods hereinafter described and claimed, and illustrated in the accompanying drawing, wherein:

Figure 1 is a diagrammatic plan-view of circuits and apparatus showing our invention in an illustrative form of embodiment; and

Fig. 2 is a simplified or diagrammatic elevational view showing the structure without the coils on the various poles of the field-frame.

In our directional element, we utilize a fourpole laminated frame-member 3, which may be either round or square, or other symmetrical shape, and which has four inwardly projecting pole-pieces, 4, 5, 6, and l, terminating in airgaps I4, l5, I6, and I1, respectively. Within the airgaps are disposed two induction-loops A and B of aluminum or other light-weight metal. These two loops are assembled at right angles to one another, one loops, A, being mounted within the other loop, B, so as to avoid. electrical coupling of the two-loop-currents. The loop A has its two coil-sides 24 and 26 within the airgaps I4 and I6, respectively. The loop B has its coil-sides 25 and 2l within the airgaps l 5 and l1, respectively. The two loops are joined together at the tops and bottoms, where they cross each other at right angles, by means of two non-conducting mounting-plates 28 and 29 (Fig. 2), to which the loops are secured by means of screws 30A and 30B. The double-loop structure is centrally pivoted on vertical pivots 3| and 32, which carry a movable contact-arm 33 for cooperating with stationary relay-contacts 34 for controlling any desired relaying-circuit which is to be controlled by our relay.

We utilize two held-fluxes which travel dian metrically across the relay, at right angles t0 each other. One flux, which we designate or, travels in a straight line through the poles 4 and B so as to interlink, and induce current in, the loop B, while reacting with the currents flowing in the coil-sides 24 and 25 of the loop A so as to produce a torque TA. The other liux, which we designate fps, extends in a straight line through the poles 5 and 1, cutting through, and inducing current in, the loop A, and reacting with the currents in the coil-sides 25 and 21 of the loop B so as to produce a torque TB.

The path for the fluxes p1 and es, inside of the loops A and B, may either be in air, or within some magnetizable material which is provided, and if magnetizable material is provided (as would be usual), it may be either rotating or stationary. We have shown a square or four-pole stationary magnetizable core-member 40 inside of, but out of contact with, the loops A and B, and held in place by any suitable means which are diagrammatically shown in the form of insulating mounting-pieces 4I and 42.

The first flux or is provided by means oi exciting-coils 54 and 56 on the poles 4 and 6, said coils being connected in series with each other and energized from a source of alternating-current energy, designated I, which may be a currentresponsive source, supplying an exciting-current m1 to the relay. The other flux on is produced by means of windings 55 and 5T on the poles 5 and 1, respectively, and these coils are shown as being connected in series with each other, and energized from an alternating-current source, designated E, which may be a voltage-responsive source, supplying the exciting-current 11E to the relay.

The operation of our relay may bc analyzed as follows.

Let the voltage-responsive current 71E, and the current-responsive current mi, supplied to the relay-coils 55-51 and Eik-53, respectively, be represented by the instantaneous values,

e-:E sin (wt-l-H) (l) i=I sin (wt-0) (2) where @e is the phase-shifting angle introduced in the voltagesource, and 9 is the angle by which I lags E.

The instantaneous fluxes rpc and pi, corresponding to the fluxes 41E and ai ol Fig. l, are

where Ks is a constant depending upon the pom tential-coi1 characteristics such as impedance and number of turns, the impedance of the induction loop A, and the coupling between the loop A and the potential coils 55 and 5l; Kb is a constant depending upon the characteristics oi the current coils 54 and 56, the impedance of the in duction loop E, and the coupling between the loop B and the current coils; Us is the angle by whic es lags E, and 0s is the angle by which pi lags I.

The induced loop currents are where Ke is a constant depending upon the cou pling between the magnetic flux and induction loop. It is the same for both induction loops due to similarity of the magnetic circuits and the induction loops. 0C is the power-factor angle or both induction loops, assuming similar magneticstructure and loop-design.

Counting clockwise torque as positive, the in* I and a line-Voltage E, these quantities I and E need not necessarily be regarded as a current and voltage, respectively, as they may be any two single-phase quantities of the same frequency, whose relative phases are to be compared in a directional-type relay. The relay operates to produce a non-pulsatory torque dependent upon the product of its two fluxes, or its two exciting-currents, times a function of the time-phase angle between them, whatever that angle may be.

The absolute symmetry of our construction makes accuracy of cancellation of the pulsating component relatively easy to obtain, and it removes the pulsating reactions from the pivotmembers 3| and 32.

The construction is also compact, and uses a minimum rotor-mass or inertia, thus making the relay extremely fast in operation.

An unexpected additional advantage of our double-loop deign is that it apparently instantly sums up the positive and negative units of power ilow, so that the usual half-cycle or more of integrating-time is not needed in order to determine the correct single-phase power-flow direction, thus producing a truly instantaneous, or more nearly instantaneous, single-phase directional i.'elayelement.

We claim as our invention:

l.. A substantially non-vibratory, product-responsive, single-phase, torque-producing relayelement, comprising a stator member and a rotor member, one of said members comprising four successive windings of an electrically excited magnetizable element, the other of said members comprising two mechanically connected loops A and B, rstand third-winding exciting-means of said electrically excited magnetizable element for causing one alternating flux to enter at one loop-side of loop A and leave at the other loop side of loop A, interlinking through loop B in the process, and secondand fourth-winding exciting-means or said electrically excited magnetizable element for causing another alternating ijlux to enter at one loop-side of loop B and leave at the othei loop-side of loop B, interlinking through loop A in the process, the two fluxes being relatively variable, both as to phase and magnitude, with respect to each other.

2. A substantially non-vibratory, product-restantaneous torques developed by the two loops 5U sponsive, single-phase, torque-producing relay- A and B are, respectively,

elementadapted for use 0n an alternating-cur- [Kbl sin (rated-06)] Each of the torques te and tb has a constant 60 rent system and comprising a stator member and component having no time-change function of time t, and a vibrating or double-frequency component involving a function of 2wt. When the torques te and tb are added, however, it will be seen that the vibrating components cancel out, being exactly equal, and 180 degrees out of phase on a double-frequency basis, or 90 degrees out of phase with respect to the line-frequency of the controlling quantities E and I.

The total torque T is thus nonpulsatory, and is 70 through loop B in the process, and secondand While our mathematical solution has thus been specifically expressed in terms of a line-current fourth-winding exciting-means of said e1ectrically excited magnetizable element for causing a line-voltage-responsive alternating flux to enter at one loop-side of loop B and leave at the other loop-side of loop B, interlinking through loop A in the process, the two i'luxes being relatively variable, both as to phase and magnitude, with respect to each other.

3. A substantially non-vibratory, product-responsive, single-phase, torque-producing relayelement, comprising a stator member and a rotor member, one of said members comprising an electrically excited magnetizable element having four exciting-winding means symmetrically disposed in two pairs of diametrically opposite means, the other of said members comprising two mechanically connected loops A and B disposed at substantially right angles to each other and having their four loop-sides disposed near the center-,lines of the respective exciting-winding means of the electrically excited magnetizable member, and two supply-circuit means for the respective pairs of diametrically opposite'means, whereby two fluxes are caused to ow diametrically across the relay-element, in the two diameters, the two fluxes being relatively variable, both as to phase and magnitude, with respect to each other. f

4. A substantially non-Vibratory, product-responsive, single-phase, torque-producing relayelement adapted for use on an alternating-current system and comprising a stator member and a rotor member, one of said members comprising an electrically excited magnetizable element having four exciting-winding means symmetrically disposed in two pairs of diametrically opposite means, the other of said members comprising two mechanically connected loops A and B disposed at substantially right angles to each other and having their four loop-sides disposed near the center-lines of the respectitve exciting-winding means of the electrically excited magnetizable member, a. line-'voltage-responsive supply-circuit means for one pair of diametrically opposite means for causing a magnetic ux to flow across one diameter of the relay-element, and a linecurrent-responsive supply-circuit means for the other pair of diametrically opposite means for causing a magnetic flux to ilow across the quadrature-related diameter of the relay-element.

5. A substantially non-vibratory single-phase torque-producing electro-responsive device comprising a movable member having a rotor-member comprising two symmetrically disposed loops at substantially right angles to each other, with one loop inside of the other, a magnetiza-ble lieldmember having four salient poles coinciding approximately with the respective loop-sides, an exciting-coil means on each pole, and energizingmeans whereby two diametrically opposite poles carry one alternating flux and the other two diametrically opposite poles carry another alternating llux.

6. A substantially non-vibratory single-phase.

" each pole, circuit-means for supplying a currentresponsive alternating exciting-current to two diametrically opposite poles, and other circuitmeans for supplying a voltage-responsive alternating exciting-current to the other two diametrically opposite poles.

7, A substantially non-vibratory alternatingcurrent torque-producing electro-responsive device comprising a magnetizable field-member and electrical means for energizing said eld-member in such manner as to cause said iield-member :to have two magnetic fluxes alternating at the same frequency and having relative magnitudes and phase-relations which are subject to change, said fluxes flowing approximately in diameters at right angles to each' other respectively, and a conducting secondary rotor-member traversed by said two diametrically iiowing fluxes and so disposed that each flux induces secondary currents which flow in a path or paths having a torque-producing relation with the other flux.

8. A substantially non-vibratory alternatingcurrent torque-producing electro-responsive device comprising a magnetizable field-member and electrical means for energizing said field-member in such manner as to cause said field-member to have two diametrically iiowing magnetic fluxes alternating at the same frequency and having relative magnitudes and phase-relations which are subject to change, said iluxes flowing approximately in diameters at right angles to each other respectively, and a secondary rotor-member comprising two mechanically-connected-t0- gether loops normally lying in planes in substantial alinement with said fluxes, respectively, and mounted so as to have a slight oscillatory movement in response .to the torque developed therein.

WILLIAM K. SONNEMANN. ARTHUR C. MEHRING. SHIRLEY L. GOLDSBOROUGH. 

